diff options
Diffstat (limited to 'block/blk-core.c')
| -rw-r--r-- | block/blk-core.c | 3371 |
1 files changed, 3371 insertions, 0 deletions
diff --git a/block/blk-core.c b/block/blk-core.c new file mode 100644 index 000000000..4c6e9ced9 --- /dev/null +++ b/block/blk-core.c @@ -0,0 +1,3371 @@ +/* + * Copyright (C) 1991, 1992 Linus Torvalds + * Copyright (C) 1994, Karl Keyte: Added support for disk statistics + * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE + * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de> + * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> + * - July2000 + * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 + */ + +/* + * This handles all read/write requests to block devices + */ +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/backing-dev.h> +#include <linux/bio.h> +#include <linux/blkdev.h> +#include <linux/blk-mq.h> +#include <linux/highmem.h> +#include <linux/mm.h> +#include <linux/kernel_stat.h> +#include <linux/string.h> +#include <linux/init.h> +#include <linux/completion.h> +#include <linux/slab.h> +#include <linux/swap.h> +#include <linux/writeback.h> +#include <linux/task_io_accounting_ops.h> +#include <linux/fault-inject.h> +#include <linux/list_sort.h> +#include <linux/delay.h> +#include <linux/ratelimit.h> +#include <linux/pm_runtime.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/block.h> + +#include "blk.h" +#include "blk-cgroup.h" +#include "blk-mq.h" + +EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); +EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); +EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); +EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); +EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); + +DEFINE_IDA(blk_queue_ida); + +int trap_non_toi_io; + +/* + * For the allocated request tables + */ +struct kmem_cache *request_cachep = NULL; + +/* + * For queue allocation + */ +struct kmem_cache *blk_requestq_cachep; + +/* + * Controlling structure to kblockd + */ +static struct workqueue_struct *kblockd_workqueue; + +void blk_queue_congestion_threshold(struct request_queue *q) +{ + int nr; + + nr = q->nr_requests - (q->nr_requests / 8) + 1; + if (nr > q->nr_requests) + nr = q->nr_requests; + q->nr_congestion_on = nr; + + nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; + if (nr < 1) + nr = 1; + q->nr_congestion_off = nr; +} + +/** + * blk_get_backing_dev_info - get the address of a queue's backing_dev_info + * @bdev: device + * + * Locates the passed device's request queue and returns the address of its + * backing_dev_info. This function can only be called if @bdev is opened + * and the return value is never NULL. + */ +struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev) +{ + struct request_queue *q = bdev_get_queue(bdev); + + return &q->backing_dev_info; +} +EXPORT_SYMBOL(blk_get_backing_dev_info); + +void blk_rq_init(struct request_queue *q, struct request *rq) +{ + memset(rq, 0, sizeof(*rq)); + + INIT_LIST_HEAD(&rq->queuelist); + INIT_LIST_HEAD(&rq->timeout_list); + rq->cpu = -1; + rq->q = q; + rq->__sector = (sector_t) -1; + INIT_HLIST_NODE(&rq->hash); + RB_CLEAR_NODE(&rq->rb_node); + rq->cmd = rq->__cmd; + rq->cmd_len = BLK_MAX_CDB; + rq->tag = -1; + rq->start_time = jiffies; + set_start_time_ns(rq); + rq->part = NULL; +} +EXPORT_SYMBOL(blk_rq_init); + +static void req_bio_endio(struct request *rq, struct bio *bio, + unsigned int nbytes, int error) +{ + if (error) + clear_bit(BIO_UPTODATE, &bio->bi_flags); + else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) + error = -EIO; + + if (unlikely(rq->cmd_flags & REQ_QUIET)) + set_bit(BIO_QUIET, &bio->bi_flags); + + bio_advance(bio, nbytes); + + /* don't actually finish bio if it's part of flush sequence */ + if (bio->bi_iter.bi_size == 0 && !(rq->cmd_flags & REQ_FLUSH_SEQ)) + bio_endio(bio, error); +} + +void blk_dump_rq_flags(struct request *rq, char *msg) +{ + int bit; + + printk(KERN_INFO "%s: dev %s: type=%x, flags=%llx\n", msg, + rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type, + (unsigned long long) rq->cmd_flags); + + printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n", + (unsigned long long)blk_rq_pos(rq), + blk_rq_sectors(rq), blk_rq_cur_sectors(rq)); + printk(KERN_INFO " bio %p, biotail %p, len %u\n", + rq->bio, rq->biotail, blk_rq_bytes(rq)); + + if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { + printk(KERN_INFO " cdb: "); + for (bit = 0; bit < BLK_MAX_CDB; bit++) + printk("%02x ", rq->cmd[bit]); + printk("\n"); + } +} +EXPORT_SYMBOL(blk_dump_rq_flags); + +static void blk_delay_work(struct work_struct *work) +{ + struct request_queue *q; + + q = container_of(work, struct request_queue, delay_work.work); + spin_lock_irq(q->queue_lock); + __blk_run_queue(q); + spin_unlock_irq(q->queue_lock); +} + +/** + * blk_delay_queue - restart queueing after defined interval + * @q: The &struct request_queue in question + * @msecs: Delay in msecs + * + * Description: + * Sometimes queueing needs to be postponed for a little while, to allow + * resources to come back. This function will make sure that queueing is + * restarted around the specified time. Queue lock must be held. + */ +void blk_delay_queue(struct request_queue *q, unsigned long msecs) +{ + if (likely(!blk_queue_dead(q))) + queue_delayed_work(kblockd_workqueue, &q->delay_work, + msecs_to_jiffies(msecs)); +} +EXPORT_SYMBOL(blk_delay_queue); + +/** + * blk_start_queue - restart a previously stopped queue + * @q: The &struct request_queue in question + * + * Description: + * blk_start_queue() will clear the stop flag on the queue, and call + * the request_fn for the queue if it was in a stopped state when + * entered. Also see blk_stop_queue(). Queue lock must be held. + **/ +void blk_start_queue(struct request_queue *q) +{ + WARN_ON(!irqs_disabled()); + + queue_flag_clear(QUEUE_FLAG_STOPPED, q); + __blk_run_queue(q); +} +EXPORT_SYMBOL(blk_start_queue); + +/** + * blk_stop_queue - stop a queue + * @q: The &struct request_queue in question + * + * Description: + * The Linux block layer assumes that a block driver will consume all + * entries on the request queue when the request_fn strategy is called. + * Often this will not happen, because of hardware limitations (queue + * depth settings). If a device driver gets a 'queue full' response, + * or if it simply chooses not to queue more I/O at one point, it can + * call this function to prevent the request_fn from being called until + * the driver has signalled it's ready to go again. This happens by calling + * blk_start_queue() to restart queue operations. Queue lock must be held. + **/ +void blk_stop_queue(struct request_queue *q) +{ + cancel_delayed_work(&q->delay_work); + queue_flag_set(QUEUE_FLAG_STOPPED, q); +} +EXPORT_SYMBOL(blk_stop_queue); + +/** + * blk_sync_queue - cancel any pending callbacks on a queue + * @q: the queue + * + * Description: + * The block layer may perform asynchronous callback activity + * on a queue, such as calling the unplug function after a timeout. + * A block device may call blk_sync_queue to ensure that any + * such activity is cancelled, thus allowing it to release resources + * that the callbacks might use. The caller must already have made sure + * that its ->make_request_fn will not re-add plugging prior to calling + * this function. + * + * This function does not cancel any asynchronous activity arising + * out of elevator or throttling code. That would require elevator_exit() + * and blkcg_exit_queue() to be called with queue lock initialized. + * + */ +void blk_sync_queue(struct request_queue *q) +{ + del_timer_sync(&q->timeout); + + if (q->mq_ops) { + struct blk_mq_hw_ctx *hctx; + int i; + + queue_for_each_hw_ctx(q, hctx, i) { + cancel_delayed_work_sync(&hctx->run_work); + cancel_delayed_work_sync(&hctx->delay_work); + } + } else { + cancel_delayed_work_sync(&q->delay_work); + } +} +EXPORT_SYMBOL(blk_sync_queue); + +/** + * __blk_run_queue_uncond - run a queue whether or not it has been stopped + * @q: The queue to run + * + * Description: + * Invoke request handling on a queue if there are any pending requests. + * May be used to restart request handling after a request has completed. + * This variant runs the queue whether or not the queue has been + * stopped. Must be called with the queue lock held and interrupts + * disabled. See also @blk_run_queue. + */ +inline void __blk_run_queue_uncond(struct request_queue *q) +{ + if (unlikely(blk_queue_dead(q))) + return; + + /* + * Some request_fn implementations, e.g. scsi_request_fn(), unlock + * the queue lock internally. As a result multiple threads may be + * running such a request function concurrently. Keep track of the + * number of active request_fn invocations such that blk_drain_queue() + * can wait until all these request_fn calls have finished. + */ + q->request_fn_active++; + q->request_fn(q); + q->request_fn_active--; +} + +/** + * __blk_run_queue - run a single device queue + * @q: The queue to run + * + * Description: + * See @blk_run_queue. This variant must be called with the queue lock + * held and interrupts disabled. + */ +void __blk_run_queue(struct request_queue *q) +{ + if (unlikely(blk_queue_stopped(q))) + return; + + __blk_run_queue_uncond(q); +} +EXPORT_SYMBOL(__blk_run_queue); + +/** + * blk_run_queue_async - run a single device queue in workqueue context + * @q: The queue to run + * + * Description: + * Tells kblockd to perform the equivalent of @blk_run_queue on behalf + * of us. The caller must hold the queue lock. + */ +void blk_run_queue_async(struct request_queue *q) +{ + if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q))) + mod_delayed_work(kblockd_workqueue, &q->delay_work, 0); +} +EXPORT_SYMBOL(blk_run_queue_async); + +/** + * blk_run_queue - run a single device queue + * @q: The queue to run + * + * Description: + * Invoke request handling on this queue, if it has pending work to do. + * May be used to restart queueing when a request has completed. + */ +void blk_run_queue(struct request_queue *q) +{ + unsigned long flags; + + spin_lock_irqsave(q->queue_lock, flags); + __blk_run_queue(q); + spin_unlock_irqrestore(q->queue_lock, flags); +} +EXPORT_SYMBOL(blk_run_queue); + +void blk_put_queue(struct request_queue *q) +{ + kobject_put(&q->kobj); +} +EXPORT_SYMBOL(blk_put_queue); + +/** + * __blk_drain_queue - drain requests from request_queue + * @q: queue to drain + * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV + * + * Drain requests from @q. If @drain_all is set, all requests are drained. + * If not, only ELVPRIV requests are drained. The caller is responsible + * for ensuring that no new requests which need to be drained are queued. + */ +static void __blk_drain_queue(struct request_queue *q, bool drain_all) + __releases(q->queue_lock) + __acquires(q->queue_lock) +{ + int i; + + lockdep_assert_held(q->queue_lock); + + while (true) { + bool drain = false; + + /* + * The caller might be trying to drain @q before its + * elevator is initialized. + */ + if (q->elevator) + elv_drain_elevator(q); + + blkcg_drain_queue(q); + + /* + * This function might be called on a queue which failed + * driver init after queue creation or is not yet fully + * active yet. Some drivers (e.g. fd and loop) get unhappy + * in such cases. Kick queue iff dispatch queue has + * something on it and @q has request_fn set. + */ + if (!list_empty(&q->queue_head) && q->request_fn) + __blk_run_queue(q); + + drain |= q->nr_rqs_elvpriv; + drain |= q->request_fn_active; + + /* + * Unfortunately, requests are queued at and tracked from + * multiple places and there's no single counter which can + * be drained. Check all the queues and counters. + */ + if (drain_all) { + struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); + drain |= !list_empty(&q->queue_head); + for (i = 0; i < 2; i++) { + drain |= q->nr_rqs[i]; + drain |= q->in_flight[i]; + if (fq) + drain |= !list_empty(&fq->flush_queue[i]); + } + } + + if (!drain) + break; + + spin_unlock_irq(q->queue_lock); + + msleep(10); + + spin_lock_irq(q->queue_lock); + } + + /* + * With queue marked dead, any woken up waiter will fail the + * allocation path, so the wakeup chaining is lost and we're + * left with hung waiters. We need to wake up those waiters. + */ + if (q->request_fn) { + struct request_list *rl; + + blk_queue_for_each_rl(rl, q) + for (i = 0; i < ARRAY_SIZE(rl->wait); i++) + wake_up_all(&rl->wait[i]); + } +} + +/** + * blk_queue_bypass_start - enter queue bypass mode + * @q: queue of interest + * + * In bypass mode, only the dispatch FIFO queue of @q is used. This + * function makes @q enter bypass mode and drains all requests which were + * throttled or issued before. On return, it's guaranteed that no request + * is being throttled or has ELVPRIV set and blk_queue_bypass() %true + * inside queue or RCU read lock. + */ +void blk_queue_bypass_start(struct request_queue *q) +{ + spin_lock_irq(q->queue_lock); + q->bypass_depth++; + queue_flag_set(QUEUE_FLAG_BYPASS, q); + spin_unlock_irq(q->queue_lock); + + /* + * Queues start drained. Skip actual draining till init is + * complete. This avoids lenghty delays during queue init which + * can happen many times during boot. + */ + if (blk_queue_init_done(q)) { + spin_lock_irq(q->queue_lock); + __blk_drain_queue(q, false); + spin_unlock_irq(q->queue_lock); + + /* ensure blk_queue_bypass() is %true inside RCU read lock */ + synchronize_rcu(); + } +} +EXPORT_SYMBOL_GPL(blk_queue_bypass_start); + +/** + * blk_queue_bypass_end - leave queue bypass mode + * @q: queue of interest + * + * Leave bypass mode and restore the normal queueing behavior. + */ +void blk_queue_bypass_end(struct request_queue *q) +{ + spin_lock_irq(q->queue_lock); + if (!--q->bypass_depth) + queue_flag_clear(QUEUE_FLAG_BYPASS, q); + WARN_ON_ONCE(q->bypass_depth < 0); + spin_unlock_irq(q->queue_lock); +} +EXPORT_SYMBOL_GPL(blk_queue_bypass_end); + +void blk_set_queue_dying(struct request_queue *q) +{ + queue_flag_set_unlocked(QUEUE_FLAG_DYING, q); + + if (q->mq_ops) + blk_mq_wake_waiters(q); + else { + struct request_list *rl; + + blk_queue_for_each_rl(rl, q) { + if (rl->rq_pool) { + wake_up(&rl->wait[BLK_RW_SYNC]); + wake_up(&rl->wait[BLK_RW_ASYNC]); + } + } + } +} +EXPORT_SYMBOL_GPL(blk_set_queue_dying); + +/** + * blk_cleanup_queue - shutdown a request queue + * @q: request queue to shutdown + * + * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and + * put it. All future requests will be failed immediately with -ENODEV. + */ +void blk_cleanup_queue(struct request_queue *q) +{ + spinlock_t *lock = q->queue_lock; + + /* mark @q DYING, no new request or merges will be allowed afterwards */ + mutex_lock(&q->sysfs_lock); + blk_set_queue_dying(q); + spin_lock_irq(lock); + + /* + * A dying queue is permanently in bypass mode till released. Note + * that, unlike blk_queue_bypass_start(), we aren't performing + * synchronize_rcu() after entering bypass mode to avoid the delay + * as some drivers create and destroy a lot of queues while + * probing. This is still safe because blk_release_queue() will be + * called only after the queue refcnt drops to zero and nothing, + * RCU or not, would be traversing the queue by then. + */ + q->bypass_depth++; + queue_flag_set(QUEUE_FLAG_BYPASS, q); + + queue_flag_set(QUEUE_FLAG_NOMERGES, q); + queue_flag_set(QUEUE_FLAG_NOXMERGES, q); + queue_flag_set(QUEUE_FLAG_DYING, q); + spin_unlock_irq(lock); + mutex_unlock(&q->sysfs_lock); + + /* + * Drain all requests queued before DYING marking. Set DEAD flag to + * prevent that q->request_fn() gets invoked after draining finished. + */ + if (q->mq_ops) { + blk_mq_freeze_queue(q); + spin_lock_irq(lock); + } else { + spin_lock_irq(lock); + __blk_drain_queue(q, true); + } + queue_flag_set(QUEUE_FLAG_DEAD, q); + spin_unlock_irq(lock); + + /* @q won't process any more request, flush async actions */ + del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer); + blk_sync_queue(q); + + if (q->mq_ops) + blk_mq_free_queue(q); + + spin_lock_irq(lock); + if (q->queue_lock != &q->__queue_lock) + q->queue_lock = &q->__queue_lock; + spin_unlock_irq(lock); + + bdi_destroy(&q->backing_dev_info); + + /* @q is and will stay empty, shutdown and put */ + blk_put_queue(q); +} +EXPORT_SYMBOL(blk_cleanup_queue); + +/* Allocate memory local to the request queue */ +static void *alloc_request_struct(gfp_t gfp_mask, void *data) +{ + int nid = (int)(long)data; + return kmem_cache_alloc_node(request_cachep, gfp_mask, nid); +} + +static void free_request_struct(void *element, void *unused) +{ + kmem_cache_free(request_cachep, element); +} + +int blk_init_rl(struct request_list *rl, struct request_queue *q, + gfp_t gfp_mask) +{ + if (unlikely(rl->rq_pool)) + return 0; + + rl->q = q; + rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0; + rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0; + init_waitqueue_head(&rl->wait[BLK_RW_SYNC]); + init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]); + + rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, alloc_request_struct, + free_request_struct, + (void *)(long)q->node, gfp_mask, + q->node); + if (!rl->rq_pool) + return -ENOMEM; + + return 0; +} + +void blk_exit_rl(struct request_list *rl) +{ + if (rl->rq_pool) + mempool_destroy(rl->rq_pool); +} + +struct request_queue *blk_alloc_queue(gfp_t gfp_mask) +{ + return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE); +} +EXPORT_SYMBOL(blk_alloc_queue); + +struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) +{ + struct request_queue *q; + int err; + + q = kmem_cache_alloc_node(blk_requestq_cachep, + gfp_mask | __GFP_ZERO, node_id); + if (!q) + return NULL; + + q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask); + if (q->id < 0) + goto fail_q; + + q->backing_dev_info.ra_pages = + (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE; + q->backing_dev_info.state = 0; + q->backing_dev_info.capabilities = 0; + q->backing_dev_info.name = "block"; + q->node = node_id; + + err = bdi_init(&q->backing_dev_info); + if (err) + goto fail_id; + + setup_timer(&q->backing_dev_info.laptop_mode_wb_timer, + laptop_mode_timer_fn, (unsigned long) q); + setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q); + INIT_LIST_HEAD(&q->queue_head); + INIT_LIST_HEAD(&q->timeout_list); + INIT_LIST_HEAD(&q->icq_list); +#ifdef CONFIG_BLK_CGROUP + INIT_LIST_HEAD(&q->blkg_list); +#endif + INIT_DELAYED_WORK(&q->delay_work, blk_delay_work); + + kobject_init(&q->kobj, &blk_queue_ktype); + + mutex_init(&q->sysfs_lock); + spin_lock_init(&q->__queue_lock); + + /* + * By default initialize queue_lock to internal lock and driver can + * override it later if need be. + */ + q->queue_lock = &q->__queue_lock; + + /* + * A queue starts its life with bypass turned on to avoid + * unnecessary bypass on/off overhead and nasty surprises during + * init. The initial bypass will be finished when the queue is + * registered by blk_register_queue(). + */ + q->bypass_depth = 1; + __set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags); + + init_waitqueue_head(&q->mq_freeze_wq); + + if (blkcg_init_queue(q)) + goto fail_bdi; + + return q; + +fail_bdi: + bdi_destroy(&q->backing_dev_info); +fail_id: + ida_simple_remove(&blk_queue_ida, q->id); +fail_q: + kmem_cache_free(blk_requestq_cachep, q); + return NULL; +} +EXPORT_SYMBOL(blk_alloc_queue_node); + +/** + * blk_init_queue - prepare a request queue for use with a block device + * @rfn: The function to be called to process requests that have been + * placed on the queue. + * @lock: Request queue spin lock + * + * Description: + * If a block device wishes to use the standard request handling procedures, + * which sorts requests and coalesces adjacent requests, then it must + * call blk_init_queue(). The function @rfn will be called when there + * are requests on the queue that need to be processed. If the device + * supports plugging, then @rfn may not be called immediately when requests + * are available on the queue, but may be called at some time later instead. + * Plugged queues are generally unplugged when a buffer belonging to one + * of the requests on the queue is needed, or due to memory pressure. + * + * @rfn is not required, or even expected, to remove all requests off the + * queue, but only as many as it can handle at a time. If it does leave + * requests on the queue, it is responsible for arranging that the requests + * get dealt with eventually. + * + * The queue spin lock must be held while manipulating the requests on the + * request queue; this lock will be taken also from interrupt context, so irq + * disabling is needed for it. + * + * Function returns a pointer to the initialized request queue, or %NULL if + * it didn't succeed. + * + * Note: + * blk_init_queue() must be paired with a blk_cleanup_queue() call + * when the block device is deactivated (such as at module unload). + **/ + +struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) +{ + return blk_init_queue_node(rfn, lock, NUMA_NO_NODE); +} +EXPORT_SYMBOL(blk_init_queue); + +struct request_queue * +blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) +{ + struct request_queue *uninit_q, *q; + + uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id); + if (!uninit_q) + return NULL; + + q = blk_init_allocated_queue(uninit_q, rfn, lock); + if (!q) + blk_cleanup_queue(uninit_q); + + return q; +} +EXPORT_SYMBOL(blk_init_queue_node); + +static void blk_queue_bio(struct request_queue *q, struct bio *bio); + +struct request_queue * +blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn, + spinlock_t *lock) +{ + if (!q) + return NULL; + + q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, 0); + if (!q->fq) + return NULL; + + if (blk_init_rl(&q->root_rl, q, GFP_KERNEL)) + goto fail; + + q->request_fn = rfn; + q->prep_rq_fn = NULL; + q->unprep_rq_fn = NULL; + q->queue_flags |= QUEUE_FLAG_DEFAULT; + + /* Override internal queue lock with supplied lock pointer */ + if (lock) + q->queue_lock = lock; + + /* + * This also sets hw/phys segments, boundary and size + */ + blk_queue_make_request(q, blk_queue_bio); + + q->sg_reserved_size = INT_MAX; + + /* Protect q->elevator from elevator_change */ + mutex_lock(&q->sysfs_lock); + + /* init elevator */ + if (elevator_init(q, NULL)) { + mutex_unlock(&q->sysfs_lock); + goto fail; + } + + mutex_unlock(&q->sysfs_lock); + + return q; + +fail: + blk_free_flush_queue(q->fq); + return NULL; +} +EXPORT_SYMBOL(blk_init_allocated_queue); + +bool blk_get_queue(struct request_queue *q) +{ + if (likely(!blk_queue_dying(q))) { + __blk_get_queue(q); + return true; + } + + return false; +} +EXPORT_SYMBOL(blk_get_queue); + +static inline void blk_free_request(struct request_list *rl, struct request *rq) +{ + if (rq->cmd_flags & REQ_ELVPRIV) { + elv_put_request(rl->q, rq); + if (rq->elv.icq) + put_io_context(rq->elv.icq->ioc); + } + + mempool_free(rq, rl->rq_pool); +} + +/* + * ioc_batching returns true if the ioc is a valid batching request and + * should be given priority access to a request. + */ +static inline int ioc_batching(struct request_queue *q, struct io_context *ioc) +{ + if (!ioc) + return 0; + + /* + * Make sure the process is able to allocate at least 1 request + * even if the batch times out, otherwise we could theoretically + * lose wakeups. + */ + return ioc->nr_batch_requests == q->nr_batching || + (ioc->nr_batch_requests > 0 + && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); +} + +/* + * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This + * will cause the process to be a "batcher" on all queues in the system. This + * is the behaviour we want though - once it gets a wakeup it should be given + * a nice run. + */ +static void ioc_set_batching(struct request_queue *q, struct io_context *ioc) +{ + if (!ioc || ioc_batching(q, ioc)) + return; + + ioc->nr_batch_requests = q->nr_batching; + ioc->last_waited = jiffies; +} + +static void __freed_request(struct request_list *rl, int sync) +{ + struct request_queue *q = rl->q; + + /* + * bdi isn't aware of blkcg yet. As all async IOs end up root + * blkcg anyway, just use root blkcg state. + */ + if (rl == &q->root_rl && + rl->count[sync] < queue_congestion_off_threshold(q)) + blk_clear_queue_congested(q, sync); + + if (rl->count[sync] + 1 <= q->nr_requests) { + if (waitqueue_active(&rl->wait[sync])) + wake_up(&rl->wait[sync]); + + blk_clear_rl_full(rl, sync); + } +} + +/* + * A request has just been released. Account for it, update the full and + * congestion status, wake up any waiters. Called under q->queue_lock. + */ +static void freed_request(struct request_list *rl, unsigned int flags) +{ + struct request_queue *q = rl->q; + int sync = rw_is_sync(flags); + + q->nr_rqs[sync]--; + rl->count[sync]--; + if (flags & REQ_ELVPRIV) + q->nr_rqs_elvpriv--; + + __freed_request(rl, sync); + + if (unlikely(rl->starved[sync ^ 1])) + __freed_request(rl, sync ^ 1); +} + +int blk_update_nr_requests(struct request_queue *q, unsigned int nr) +{ + struct request_list *rl; + + spin_lock_irq(q->queue_lock); + q->nr_requests = nr; + blk_queue_congestion_threshold(q); + + /* congestion isn't cgroup aware and follows root blkcg for now */ + rl = &q->root_rl; + + if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q)) + blk_set_queue_congested(q, BLK_RW_SYNC); + else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q)) + blk_clear_queue_congested(q, BLK_RW_SYNC); + + if (rl->count[BLK_RW_ASYNC] >= queue_congestion_on_threshold(q)) + blk_set_queue_congested(q, BLK_RW_ASYNC); + else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q)) + blk_clear_queue_congested(q, BLK_RW_ASYNC); + + blk_queue_for_each_rl(rl, q) { + if (rl->count[BLK_RW_SYNC] >= q->nr_requests) { + blk_set_rl_full(rl, BLK_RW_SYNC); + } else { + blk_clear_rl_full(rl, BLK_RW_SYNC); + wake_up(&rl->wait[BLK_RW_SYNC]); + } + + if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) { + blk_set_rl_full(rl, BLK_RW_ASYNC); + } else { + blk_clear_rl_full(rl, BLK_RW_ASYNC); + wake_up(&rl->wait[BLK_RW_ASYNC]); + } + } + + spin_unlock_irq(q->queue_lock); + return 0; +} + +/* + * Determine if elevator data should be initialized when allocating the + * request associated with @bio. + */ +static bool blk_rq_should_init_elevator(struct bio *bio) +{ + if (!bio) + return true; + + /* + * Flush requests do not use the elevator so skip initialization. + * This allows a request to share the flush and elevator data. + */ + if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) + return false; + + return true; +} + +/** + * rq_ioc - determine io_context for request allocation + * @bio: request being allocated is for this bio (can be %NULL) + * + * Determine io_context to use for request allocation for @bio. May return + * %NULL if %current->io_context doesn't exist. + */ +static struct io_context *rq_ioc(struct bio *bio) +{ +#ifdef CONFIG_BLK_CGROUP + if (bio && bio->bi_ioc) + return bio->bi_ioc; +#endif + return current->io_context; +} + +/** + * __get_request - get a free request + * @rl: request list to allocate from + * @rw_flags: RW and SYNC flags + * @bio: bio to allocate request for (can be %NULL) + * @gfp_mask: allocation mask + * + * Get a free request from @q. This function may fail under memory + * pressure or if @q is dead. + * + * Must be called with @q->queue_lock held and, + * Returns ERR_PTR on failure, with @q->queue_lock held. + * Returns request pointer on success, with @q->queue_lock *not held*. + */ +static struct request *__get_request(struct request_list *rl, int rw_flags, + struct bio *bio, gfp_t gfp_mask) +{ + struct request_queue *q = rl->q; + struct request *rq; + struct elevator_type *et = q->elevator->type; + struct io_context *ioc = rq_ioc(bio); + struct io_cq *icq = NULL; + const bool is_sync = rw_is_sync(rw_flags) != 0; + int may_queue; + + if (unlikely(blk_queue_dying(q))) + return ERR_PTR(-ENODEV); + + may_queue = elv_may_queue(q, rw_flags); + if (may_queue == ELV_MQUEUE_NO) + goto rq_starved; + + if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) { + if (rl->count[is_sync]+1 >= q->nr_requests) { + /* + * The queue will fill after this allocation, so set + * it as full, and mark this process as "batching". + * This process will be allowed to complete a batch of + * requests, others will be blocked. + */ + if (!blk_rl_full(rl, is_sync)) { + ioc_set_batching(q, ioc); + blk_set_rl_full(rl, is_sync); + } else { + if (may_queue != ELV_MQUEUE_MUST + && !ioc_batching(q, ioc)) { + /* + * The queue is full and the allocating + * process is not a "batcher", and not + * exempted by the IO scheduler + */ + return ERR_PTR(-ENOMEM); + } + } + } + /* + * bdi isn't aware of blkcg yet. As all async IOs end up + * root blkcg anyway, just use root blkcg state. + */ + if (rl == &q->root_rl) + blk_set_queue_congested(q, is_sync); + } + + /* + * Only allow batching queuers to allocate up to 50% over the defined + * limit of requests, otherwise we could have thousands of requests + * allocated with any setting of ->nr_requests + */ + if (rl->count[is_sync] >= (3 * q->nr_requests / 2)) + return ERR_PTR(-ENOMEM); + + q->nr_rqs[is_sync]++; + rl->count[is_sync]++; + rl->starved[is_sync] = 0; + + /* + * Decide whether the new request will be managed by elevator. If + * so, mark @rw_flags and increment elvpriv. Non-zero elvpriv will + * prevent the current elevator from being destroyed until the new + * request is freed. This guarantees icq's won't be destroyed and + * makes creating new ones safe. + * + * Also, lookup icq while holding queue_lock. If it doesn't exist, + * it will be created after releasing queue_lock. + */ + if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) { + rw_flags |= REQ_ELVPRIV; + q->nr_rqs_elvpriv++; + if (et->icq_cache && ioc) + icq = ioc_lookup_icq(ioc, q); + } + + if (blk_queue_io_stat(q)) + rw_flags |= REQ_IO_STAT; + spin_unlock_irq(q->queue_lock); + + /* allocate and init request */ + rq = mempool_alloc(rl->rq_pool, gfp_mask); + if (!rq) + goto fail_alloc; + + blk_rq_init(q, rq); + blk_rq_set_rl(rq, rl); + rq->cmd_flags = rw_flags | REQ_ALLOCED; + + /* init elvpriv */ + if (rw_flags & REQ_ELVPRIV) { + if (unlikely(et->icq_cache && !icq)) { + if (ioc) + icq = ioc_create_icq(ioc, q, gfp_mask); + if (!icq) + goto fail_elvpriv; + } + + rq->elv.icq = icq; + if (unlikely(elv_set_request(q, rq, bio, gfp_mask))) + goto fail_elvpriv; + + /* @rq->elv.icq holds io_context until @rq is freed */ + if (icq) + get_io_context(icq->ioc); + } +out: + /* + * ioc may be NULL here, and ioc_batching will be false. That's + * OK, if the queue is under the request limit then requests need + * not count toward the nr_batch_requests limit. There will always + * be some limit enforced by BLK_BATCH_TIME. + */ + if (ioc_batching(q, ioc)) + ioc->nr_batch_requests--; + + trace_block_getrq(q, bio, rw_flags & 1); + return rq; + +fail_elvpriv: + /* + * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed + * and may fail indefinitely under memory pressure and thus + * shouldn't stall IO. Treat this request as !elvpriv. This will + * disturb iosched and blkcg but weird is bettern than dead. + */ + printk_ratelimited(KERN_WARNING "%s: dev %s: request aux data allocation failed, iosched may be disturbed\n", + __func__, dev_name(q->backing_dev_info.dev)); + + rq->cmd_flags &= ~REQ_ELVPRIV; + rq->elv.icq = NULL; + + spin_lock_irq(q->queue_lock); + q->nr_rqs_elvpriv--; + spin_unlock_irq(q->queue_lock); + goto out; + +fail_alloc: + /* + * Allocation failed presumably due to memory. Undo anything we + * might have messed up. + * + * Allocating task should really be put onto the front of the wait + * queue, but this is pretty rare. + */ + spin_lock_irq(q->queue_lock); + freed_request(rl, rw_flags); + + /* + * in the very unlikely event that allocation failed and no + * requests for this direction was pending, mark us starved so that + * freeing of a request in the other direction will notice + * us. another possible fix would be to split the rq mempool into + * READ and WRITE + */ +rq_starved: + if (unlikely(rl->count[is_sync] == 0)) + rl->starved[is_sync] = 1; + return ERR_PTR(-ENOMEM); +} + +/** + * get_request - get a free request + * @q: request_queue to allocate request from + * @rw_flags: RW and SYNC flags + * @bio: bio to allocate request for (can be %NULL) + * @gfp_mask: allocation mask + * + * Get a free request from @q. If %__GFP_WAIT is set in @gfp_mask, this + * function keeps retrying under memory pressure and fails iff @q is dead. + * + * Must be called with @q->queue_lock held and, + * Returns ERR_PTR on failure, with @q->queue_lock held. + * Returns request pointer on success, with @q->queue_lock *not held*. + */ +static struct request *get_request(struct request_queue *q, int rw_flags, + struct bio *bio, gfp_t gfp_mask) +{ + const bool is_sync = rw_is_sync(rw_flags) != 0; + DEFINE_WAIT(wait); + struct request_list *rl; + struct request *rq; + + rl = blk_get_rl(q, bio); /* transferred to @rq on success */ +retry: + rq = __get_request(rl, rw_flags, bio, gfp_mask); + if (!IS_ERR(rq)) + return rq; + + if (!(gfp_mask & __GFP_WAIT) || unlikely(blk_queue_dying(q))) { + blk_put_rl(rl); + return rq; + } + + /* wait on @rl and retry */ + prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, + TASK_UNINTERRUPTIBLE); + + trace_block_sleeprq(q, bio, rw_flags & 1); + + spin_unlock_irq(q->queue_lock); + io_schedule(); + + /* + * After sleeping, we become a "batching" process and will be able + * to allocate at least one request, and up to a big batch of them + * for a small period time. See ioc_batching, ioc_set_batching + */ + ioc_set_batching(q, current->io_context); + + spin_lock_irq(q->queue_lock); + finish_wait(&rl->wait[is_sync], &wait); + + goto retry; +} + +static struct request *blk_old_get_request(struct request_queue *q, int rw, + gfp_t gfp_mask) +{ + struct request *rq; + + BUG_ON(rw != READ && rw != WRITE); + + /* create ioc upfront */ + create_io_context(gfp_mask, q->node); + + spin_lock_irq(q->queue_lock); + rq = get_request(q, rw, NULL, gfp_mask); + if (IS_ERR(rq)) + spin_unlock_irq(q->queue_lock); + /* q->queue_lock is unlocked at this point */ + + return rq; +} + +struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask) +{ + if (q->mq_ops) + return blk_mq_alloc_request(q, rw, gfp_mask, false); + else + return blk_old_get_request(q, rw, gfp_mask); +} +EXPORT_SYMBOL(blk_get_request); + +/** + * blk_make_request - given a bio, allocate a corresponding struct request. + * @q: target request queue + * @bio: The bio describing the memory mappings that will be submitted for IO. + * It may be a chained-bio properly constructed by block/bio layer. + * @gfp_mask: gfp flags to be used for memory allocation + * + * blk_make_request is the parallel of generic_make_request for BLOCK_PC + * type commands. Where the struct request needs to be farther initialized by + * the caller. It is passed a &struct bio, which describes the memory info of + * the I/O transfer. + * + * The caller of blk_make_request must make sure that bi_io_vec + * are set to describe the memory buffers. That bio_data_dir() will return + * the needed direction of the request. (And all bio's in the passed bio-chain + * are properly set accordingly) + * + * If called under none-sleepable conditions, mapped bio buffers must not + * need bouncing, by calling the appropriate masked or flagged allocator, + * suitable for the target device. Otherwise the call to blk_queue_bounce will + * BUG. + * + * WARNING: When allocating/cloning a bio-chain, careful consideration should be + * given to how you allocate bios. In particular, you cannot use __GFP_WAIT for + * anything but the first bio in the chain. Otherwise you risk waiting for IO + * completion of a bio that hasn't been submitted yet, thus resulting in a + * deadlock. Alternatively bios should be allocated using bio_kmalloc() instead + * of bio_alloc(), as that avoids the mempool deadlock. + * If possible a big IO should be split into smaller parts when allocation + * fails. Partial allocation should not be an error, or you risk a live-lock. + */ +struct request *blk_make_request(struct request_queue *q, struct bio *bio, + gfp_t gfp_mask) +{ + struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask); + + if (IS_ERR(rq)) + return rq; + + blk_rq_set_block_pc(rq); + + for_each_bio(bio) { + struct bio *bounce_bio = bio; + int ret; + + blk_queue_bounce(q, &bounce_bio); + ret = blk_rq_append_bio(q, rq, bounce_bio); + if (unlikely(ret)) { + blk_put_request(rq); + return ERR_PTR(ret); + } + } + + return rq; +} +EXPORT_SYMBOL(blk_make_request); + +/** + * blk_rq_set_block_pc - initialize a request to type BLOCK_PC + * @rq: request to be initialized + * + */ +void blk_rq_set_block_pc(struct request *rq) +{ + rq->cmd_type = REQ_TYPE_BLOCK_PC; + rq->__data_len = 0; + rq->__sector = (sector_t) -1; + rq->bio = rq->biotail = NULL; + memset(rq->__cmd, 0, sizeof(rq->__cmd)); +} +EXPORT_SYMBOL(blk_rq_set_block_pc); + +/** + * blk_requeue_request - put a request back on queue + * @q: request queue where request should be inserted + * @rq: request to be inserted + * + * Description: + * Drivers often keep queueing requests until the hardware cannot accept + * more, when that condition happens we need to put the request back + * on the queue. Must be called with queue lock held. + */ +void blk_requeue_request(struct request_queue *q, struct request *rq) +{ + blk_delete_timer(rq); + blk_clear_rq_complete(rq); + trace_block_rq_requeue(q, rq); + + if (rq->cmd_flags & REQ_QUEUED) + blk_queue_end_tag(q, rq); + + BUG_ON(blk_queued_rq(rq)); + + elv_requeue_request(q, rq); +} +EXPORT_SYMBOL(blk_requeue_request); + +static void add_acct_request(struct request_queue *q, struct request *rq, + int where) +{ + blk_account_io_start(rq, true); + __elv_add_request(q, rq, where); +} + +static void part_round_stats_single(int cpu, struct hd_struct *part, + unsigned long now) +{ + int inflight; + + if (now == part->stamp) + return; + + inflight = part_in_flight(part); + if (inflight) { + __part_stat_add(cpu, part, time_in_queue, + inflight * (now - part->stamp)); + __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); + } + part->stamp = now; +} + +/** + * part_round_stats() - Round off the performance stats on a struct disk_stats. + * @cpu: cpu number for stats access + * @part: target partition + * + * The average IO queue length and utilisation statistics are maintained + * by observing the current state of the queue length and the amount of + * time it has been in this state for. + * + * Normally, that accounting is done on IO completion, but that can result + * in more than a second's worth of IO being accounted for within any one + * second, leading to >100% utilisation. To deal with that, we call this + * function to do a round-off before returning the results when reading + * /proc/diskstats. This accounts immediately for all queue usage up to + * the current jiffies and restarts the counters again. + */ +void part_round_stats(int cpu, struct hd_struct *part) +{ + unsigned long now = jiffies; + + if (part->partno) + part_round_stats_single(cpu, &part_to_disk(part)->part0, now); + part_round_stats_single(cpu, part, now); +} +EXPORT_SYMBOL_GPL(part_round_stats); + +#ifdef CONFIG_PM +static void blk_pm_put_request(struct request *rq) +{ + if (rq->q->dev && !(rq->cmd_flags & REQ_PM) && !--rq->q->nr_pending) + pm_runtime_mark_last_busy(rq->q->dev); +} +#else +static inline void blk_pm_put_request(struct request *rq) {} +#endif + +/* + * queue lock must be held + */ +void __blk_put_request(struct request_queue *q, struct request *req) +{ + if (unlikely(!q)) + return; + + if (q->mq_ops) { + blk_mq_free_request(req); + return; + } + + blk_pm_put_request(req); + + elv_completed_request(q, req); + + /* this is a bio leak */ + WARN_ON(req->bio != NULL); + + /* + * Request may not have originated from ll_rw_blk. if not, + * it didn't come out of our reserved rq pools + */ + if (req->cmd_flags & REQ_ALLOCED) { + unsigned int flags = req->cmd_flags; + struct request_list *rl = blk_rq_rl(req); + + BUG_ON(!list_empty(&req->queuelist)); + BUG_ON(ELV_ON_HASH(req)); + + blk_free_request(rl, req); + freed_request(rl, flags); + blk_put_rl(rl); + } +} +EXPORT_SYMBOL_GPL(__blk_put_request); + +void blk_put_request(struct request *req) +{ + struct request_queue *q = req->q; + + if (q->mq_ops) + blk_mq_free_request(req); + else { + unsigned long flags; + + spin_lock_irqsave(q->queue_lock, flags); + __blk_put_request(q, req); + spin_unlock_irqrestore(q->queue_lock, flags); + } +} +EXPORT_SYMBOL(blk_put_request); + +/** + * blk_add_request_payload - add a payload to a request + * @rq: request to update + * @page: page backing the payload + * @len: length of the payload. + * + * This allows to later add a payload to an already submitted request by + * a block driver. The driver needs to take care of freeing the payload + * itself. + * + * Note that this is a quite horrible hack and nothing but handling of + * discard requests should ever use it. + */ +void blk_add_request_payload(struct request *rq, struct page *page, + unsigned int len) +{ + struct bio *bio = rq->bio; + + bio->bi_io_vec->bv_page = page; + bio->bi_io_vec->bv_offset = 0; + bio->bi_io_vec->bv_len = len; + + bio->bi_iter.bi_size = len; + bio->bi_vcnt = 1; + bio->bi_phys_segments = 1; + + rq->__data_len = rq->resid_len = len; + rq->nr_phys_segments = 1; +} +EXPORT_SYMBOL_GPL(blk_add_request_payload); + +bool bio_attempt_back_merge(struct request_queue *q, struct request *req, + struct bio *bio) +{ + const int ff = bio->bi_rw & REQ_FAILFAST_MASK; + + if (!ll_back_merge_fn(q, req, bio)) + return false; + + trace_block_bio_backmerge(q, req, bio); + + if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) + blk_rq_set_mixed_merge(req); + + req->biotail->bi_next = bio; + req->biotail = bio; + req->__data_len += bio->bi_iter.bi_size; + req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); + + blk_account_io_start(req, false); + return true; +} + +bool bio_attempt_front_merge(struct request_queue *q, struct request *req, + struct bio *bio) +{ + const int ff = bio->bi_rw & REQ_FAILFAST_MASK; + + if (!ll_front_merge_fn(q, req, bio)) + return false; + + trace_block_bio_frontmerge(q, req, bio); + + if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) + blk_rq_set_mixed_merge(req); + + bio->bi_next = req->bio; + req->bio = bio; + + req->__sector = bio->bi_iter.bi_sector; + req->__data_len += bio->bi_iter.bi_size; + req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); + + blk_account_io_start(req, false); + return true; +} + +/** + * blk_attempt_plug_merge - try to merge with %current's plugged list + * @q: request_queue new bio is being queued at + * @bio: new bio being queued + * @request_count: out parameter for number of traversed plugged requests + * + * Determine whether @bio being queued on @q can be merged with a request + * on %current's plugged list. Returns %true if merge was successful, + * otherwise %false. + * + * Plugging coalesces IOs from the same issuer for the same purpose without + * going through @q->queue_lock. As such it's more of an issuing mechanism + * than scheduling, and the request, while may have elvpriv data, is not + * added on the elevator at this point. In addition, we don't have + * reliable access to the elevator outside queue lock. Only check basic + * merging parameters without querying the elevator. + * + * Caller must ensure !blk_queue_nomerges(q) beforehand. + */ +bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, + unsigned int *request_count) +{ + struct blk_plug *plug; + struct request *rq; + bool ret = false; + struct list_head *plug_list; + + plug = current->plug; + if (!plug) + goto out; + *request_count = 0; + + if (q->mq_ops) + plug_list = &plug->mq_list; + else + plug_list = &plug->list; + + list_for_each_entry_reverse(rq, plug_list, queuelist) { + int el_ret; + + if (rq->q == q) + (*request_count)++; + + if (rq->q != q || !blk_rq_merge_ok(rq, bio)) + continue; + + el_ret = blk_try_merge(rq, bio); + if (el_ret == ELEVATOR_BACK_MERGE) { + ret = bio_attempt_back_merge(q, rq, bio); + if (ret) + break; + } else if (el_ret == ELEVATOR_FRONT_MERGE) { + ret = bio_attempt_front_merge(q, rq, bio); + if (ret) + break; + } + } +out: + return ret; +} + +void init_request_from_bio(struct request *req, struct bio *bio) +{ + req->cmd_type = REQ_TYPE_FS; + + req->cmd_flags |= bio->bi_rw & REQ_COMMON_MASK; + if (bio->bi_rw & REQ_RAHEAD) + req->cmd_flags |= REQ_FAILFAST_MASK; + + req->errors = 0; + req->__sector = bio->bi_iter.bi_sector; + req->ioprio = bio_prio(bio); + blk_rq_bio_prep(req->q, req, bio); +} + +static void blk_queue_bio(struct request_queue *q, struct bio *bio) +{ + const bool sync = !!(bio->bi_rw & REQ_SYNC); + struct blk_plug *plug; + int el_ret, rw_flags, where = ELEVATOR_INSERT_SORT; + struct request *req; + unsigned int request_count = 0; + + /* + * low level driver can indicate that it wants pages above a + * certain limit bounced to low memory (ie for highmem, or even + * ISA dma in theory) + */ + blk_queue_bounce(q, &bio); + + if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { + bio_endio(bio, -EIO); + return; + } + + if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) { + spin_lock_irq(q->queue_lock); + where = ELEVATOR_INSERT_FLUSH; + goto get_rq; + } + + /* + * Check if we can merge with the plugged list before grabbing + * any locks. + */ + if (!blk_queue_nomerges(q) && + blk_attempt_plug_merge(q, bio, &request_count)) + return; + + spin_lock_irq(q->queue_lock); + + el_ret = elv_merge(q, &req, bio); + if (el_ret == ELEVATOR_BACK_MERGE) { + if (bio_attempt_back_merge(q, req, bio)) { + elv_bio_merged(q, req, bio); + if (!attempt_back_merge(q, req)) + elv_merged_request(q, req, el_ret); + goto out_unlock; + } + } else if (el_ret == ELEVATOR_FRONT_MERGE) { + if (bio_attempt_front_merge(q, req, bio)) { + elv_bio_merged(q, req, bio); + if (!attempt_front_merge(q, req)) + elv_merged_request(q, req, el_ret); + goto out_unlock; + } + } + +get_rq: + /* + * This sync check and mask will be re-done in init_request_from_bio(), + * but we need to set it earlier to expose the sync flag to the + * rq allocator and io schedulers. + */ + rw_flags = bio_data_dir(bio); + if (sync) + rw_flags |= REQ_SYNC; + + /* + * Grab a free request. This is might sleep but can not fail. + * Returns with the queue unlocked. + */ + req = get_request(q, rw_flags, bio, GFP_NOIO); + if (IS_ERR(req)) { + bio_endio(bio, PTR_ERR(req)); /* @q is dead */ + goto out_unlock; + } + + /* + * After dropping the lock and possibly sleeping here, our request + * may now be mergeable after it had proven unmergeable (above). + * We don't worry about that case for efficiency. It won't happen + * often, and the elevators are able to handle it. + */ + init_request_from_bio(req, bio); + + if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags)) + req->cpu = raw_smp_processor_id(); + + plug = current->plug; + if (plug) { + /* + * If this is the first request added after a plug, fire + * of a plug trace. + */ + if (!request_count) + trace_block_plug(q); + else { + if (request_count >= BLK_MAX_REQUEST_COUNT) { + blk_flush_plug_list(plug, false); + trace_block_plug(q); + } + } + list_add_tail(&req->queuelist, &plug->list); + blk_account_io_start(req, true); + } else { + spin_lock_irq(q->queue_lock); + add_acct_request(q, req, where); + __blk_run_queue(q); +out_unlock: + spin_unlock_irq(q->queue_lock); + } +} + +/* + * If bio->bi_dev is a partition, remap the location + */ +static inline void blk_partition_remap(struct bio *bio) +{ + struct block_device *bdev = bio->bi_bdev; + + if (bio_sectors(bio) && bdev != bdev->bd_contains) { + struct hd_struct *p = bdev->bd_part; + + bio->bi_iter.bi_sector += p->start_sect; + bio->bi_bdev = bdev->bd_contains; + + trace_block_bio_remap(bdev_get_queue(bio->bi_bdev), bio, + bdev->bd_dev, + bio->bi_iter.bi_sector - p->start_sect); + } +} + +static void handle_bad_sector(struct bio *bio) +{ + char b[BDEVNAME_SIZE]; + + printk(KERN_INFO "attempt to access beyond end of device\n"); + printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n", + bdevname(bio->bi_bdev, b), + bio->bi_rw, + (unsigned long long)bio_end_sector(bio), + (long long)(i_size_read(bio->bi_bdev->bd_inode) >> 9)); + + set_bit(BIO_EOF, &bio->bi_flags); +} + +#ifdef CONFIG_FAIL_MAKE_REQUEST + +static DECLARE_FAULT_ATTR(fail_make_request); + +static int __init setup_fail_make_request(char *str) +{ + return setup_fault_attr(&fail_make_request, str); +} +__setup("fail_make_request=", setup_fail_make_request); + +static bool should_fail_request(struct hd_struct *part, unsigned int bytes) +{ + return part->make_it_fail && should_fail(&fail_make_request, bytes); +} + +static int __init fail_make_request_debugfs(void) +{ + struct dentry *dir = fault_create_debugfs_attr("fail_make_request", + NULL, &fail_make_request); + + return PTR_ERR_OR_ZERO(dir); +} + +late_initcall(fail_make_request_debugfs); + +#else /* CONFIG_FAIL_MAKE_REQUEST */ + +static inline bool should_fail_request(struct hd_struct *part, + unsigned int bytes) +{ + return false; +} + +#endif /* CONFIG_FAIL_MAKE_REQUEST */ + +/* + * Check whether this bio extends beyond the end of the device. + */ +static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors) +{ + sector_t maxsector; + + if (!nr_sectors) + return 0; + + /* Test device or partition size, when known. */ + maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9; + if (maxsector) { + sector_t sector = bio->bi_iter.bi_sector; + + if (maxsector < nr_sectors || maxsector - nr_sectors < sector) { + /* + * This may well happen - the kernel calls bread() + * without checking the size of the device, e.g., when + * mounting a device. + */ + handle_bad_sector(bio); + return 1; + } + } + + return 0; +} + +static noinline_for_stack bool +generic_make_request_checks(struct bio *bio) +{ + struct request_queue *q; + int nr_sectors = bio_sectors(bio); + int err = -EIO; + char b[BDEVNAME_SIZE]; + struct hd_struct *part; + + might_sleep(); + + if (bio_check_eod(bio, nr_sectors)) + goto end_io; + + q = bdev_get_queue(bio->bi_bdev); + if (unlikely(!q)) { + printk(KERN_ERR + "generic_make_request: Trying to access " + "nonexistent block-device %s (%Lu)\n", + bdevname(bio->bi_bdev, b), + (long long) bio->bi_iter.bi_sector); + goto end_io; + } + + if (likely(bio_is_rw(bio) && + nr_sectors > queue_max_hw_sectors(q))) { + printk(KERN_ERR "bio too big device %s (%u > %u)\n", + bdevname(bio->bi_bdev, b), + bio_sectors(bio), + queue_max_hw_sectors(q)); + goto end_io; + } + + part = bio->bi_bdev->bd_part; + if (should_fail_request(part, bio->bi_iter.bi_size) || + should_fail_request(&part_to_disk(part)->part0, + bio->bi_iter.bi_size)) + goto end_io; + + /* + * If this device has partitions, remap block n + * of partition p to block n+start(p) of the disk. + */ + blk_partition_remap(bio); + + if (bio_check_eod(bio, nr_sectors)) + goto end_io; + + /* + * Filter flush bio's early so that make_request based + * drivers without flush support don't have to worry + * about them. + */ + if ((bio->bi_rw & (REQ_FLUSH | REQ_FUA)) && !q->flush_flags) { + bio->bi_rw &= ~(REQ_FLUSH | REQ_FUA); + if (!nr_sectors) { + err = 0; + goto end_io; + } + } + + if ((bio->bi_rw & REQ_DISCARD) && + (!blk_queue_discard(q) || + ((bio->bi_rw & REQ_SECURE) && !blk_queue_secdiscard(q)))) { + err = -EOPNOTSUPP; + goto end_io; + } + + if (bio->bi_rw & REQ_WRITE_SAME && !bdev_write_same(bio->bi_bdev)) { + err = -EOPNOTSUPP; + goto end_io; + } + + /* + * Various block parts want %current->io_context and lazy ioc + * allocation ends up trading a lot of pain for a small amount of + * memory. Just allocate it upfront. This may fail and block + * layer knows how to live with it. + */ + create_io_context(GFP_ATOMIC, q->node); + + if (blk_throtl_bio(q, bio)) + return false; /* throttled, will be resubmitted later */ + + trace_block_bio_queue(q, bio); + return true; + +end_io: + bio_endio(bio, err); + return false; +} + +/** + * generic_make_request - hand a buffer to its device driver for I/O + * @bio: The bio describing the location in memory and on the device. + * + * generic_make_request() is used to make I/O requests of block + * devices. It is passed a &struct bio, which describes the I/O that needs + * to be done. + * + * generic_make_request() does not return any status. The + * success/failure status of the request, along with notification of + * completion, is delivered asynchronously through the bio->bi_end_io + * function described (one day) else where. + * + * The caller of generic_make_request must make sure that bi_io_vec + * are set to describe the memory buffer, and that bi_dev and bi_sector are + * set to describe the device address, and the + * bi_end_io and optionally bi_private are set to describe how + * completion notification should be signaled. + * + * generic_make_request and the drivers it calls may use bi_next if this + * bio happens to be merged with someone else, and may resubmit the bio to + * a lower device by calling into generic_make_request recursively, which + * means the bio should NOT be touched after the call to ->make_request_fn. + */ +void generic_make_request(struct bio *bio) +{ + struct bio_list bio_list_on_stack; + + if (!generic_make_request_checks(bio)) + return; + + /* + * We only want one ->make_request_fn to be active at a time, else + * stack usage with stacked devices could be a problem. So use + * current->bio_list to keep a list of requests submited by a + * make_request_fn function. current->bio_list is also used as a + * flag to say if generic_make_request is currently active in this + * task or not. If it is NULL, then no make_request is active. If + * it is non-NULL, then a make_request is active, and new requests + * should be added at the tail + */ + if (current->bio_list) { + bio_list_add(current->bio_list, bio); + return; + } + + /* following loop may be a bit non-obvious, and so deserves some + * explanation. + * Before entering the loop, bio->bi_next is NULL (as all callers + * ensure that) so we have a list with a single bio. + * We pretend that we have just taken it off a longer list, so + * we assign bio_list to a pointer to the bio_list_on_stack, + * thus initialising the bio_list of new bios to be + * added. ->make_request() may indeed add some more bios + * through a recursive call to generic_make_request. If it + * did, we find a non-NULL value in bio_list and re-enter the loop + * from the top. In this case we really did just take the bio + * of the top of the list (no pretending) and so remove it from + * bio_list, and call into ->make_request() again. + */ + BUG_ON(bio->bi_next); + bio_list_init(&bio_list_on_stack); + current->bio_list = &bio_list_on_stack; + do { + struct request_queue *q = bdev_get_queue(bio->bi_bdev); + + q->make_request_fn(q, bio); + + bio = bio_list_pop(current->bio_list); + } while (bio); + current->bio_list = NULL; /* deactivate */ +} +EXPORT_SYMBOL(generic_make_request); + +/** + * submit_bio - submit a bio to the block device layer for I/O + * @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead) + * @bio: The &struct bio which describes the I/O + * + * submit_bio() is very similar in purpose to generic_make_request(), and + * uses that function to do most of the work. Both are fairly rough + * interfaces; @bio must be presetup and ready for I/O. + * + */ +void submit_bio(int rw, struct bio *bio) +{ + bio->bi_rw |= rw; + + if (unlikely(trap_non_toi_io)) + BUG_ON(!(bio->bi_flags & BIO_TOI)); + + /* + * If it's a regular read/write or a barrier with data attached, + * go through the normal accounting stuff before submission. + */ + if (bio_has_data(bio)) { + unsigned int count; + + if (unlikely(rw & REQ_WRITE_SAME)) + count = bdev_logical_block_size(bio->bi_bdev) >> 9; + else + count = bio_sectors(bio); + + if (rw & WRITE) { + count_vm_events(PGPGOUT, count); + } else { + task_io_account_read(bio->bi_iter.bi_size); + count_vm_events(PGPGIN, count); + } + + if (unlikely(block_dump)) { + char b[BDEVNAME_SIZE]; + printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n", + current->comm, task_pid_nr(current), + (rw & WRITE) ? "WRITE" : "READ", + (unsigned long long)bio->bi_iter.bi_sector, + bdevname(bio->bi_bdev, b), + count); + } + } + + generic_make_request(bio); +} +EXPORT_SYMBOL(submit_bio); + +/** + * blk_rq_check_limits - Helper function to check a request for the queue limit + * @q: the queue + * @rq: the request being checked + * + * Description: + * @rq may have been made based on weaker limitations of upper-level queues + * in request stacking drivers, and it may violate the limitation of @q. + * Since the block layer and the underlying device driver trust @rq + * after it is inserted to @q, it should be checked against @q before + * the insertion using this generic function. + * + * This function should also be useful for request stacking drivers + * in some cases below, so export this function. + * Request stacking drivers like request-based dm may change the queue + * limits while requests are in the queue (e.g. dm's table swapping). + * Such request stacking drivers should check those requests against + * the new queue limits again when they dispatch those requests, + * although such checkings are also done against the old queue limits + * when submitting requests. + */ +int blk_rq_check_limits(struct request_queue *q, struct request *rq) +{ + if (!rq_mergeable(rq)) + return 0; + + if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, rq->cmd_flags)) { + printk(KERN_ERR "%s: over max size limit.\n", __func__); + return -EIO; + } + + /* + * queue's settings related to segment counting like q->bounce_pfn + * may differ from that of other stacking queues. + * Recalculate it to check the request correctly on this queue's + * limitation. + */ + blk_recalc_rq_segments(rq); + if (rq->nr_phys_segments > queue_max_segments(q)) { + printk(KERN_ERR "%s: over max segments limit.\n", __func__); + return -EIO; + } + + return 0; +} +EXPORT_SYMBOL_GPL(blk_rq_check_limits); + +/** + * blk_insert_cloned_request - Helper for stacking drivers to submit a request + * @q: the queue to submit the request + * @rq: the request being queued + */ +int blk_insert_cloned_request(struct request_queue *q, struct request *rq) +{ + unsigned long flags; + int where = ELEVATOR_INSERT_BACK; + + if (blk_rq_check_limits(q, rq)) + return -EIO; + + if (rq->rq_disk && + should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq))) + return -EIO; + + if (q->mq_ops) { + if (blk_queue_io_stat(q)) + blk_account_io_start(rq, true); + blk_mq_insert_request(rq, false, true, true); + return 0; + } + + spin_lock_irqsave(q->queue_lock, flags); + if (unlikely(blk_queue_dying(q))) { + spin_unlock_irqrestore(q->queue_lock, flags); + return -ENODEV; + } + + /* + * Submitting request must be dequeued before calling this function + * because it will be linked to another request_queue + */ + BUG_ON(blk_queued_rq(rq)); + + if (rq->cmd_flags & (REQ_FLUSH|REQ_FUA)) + where = ELEVATOR_INSERT_FLUSH; + + add_acct_request(q, rq, where); + if (where == ELEVATOR_INSERT_FLUSH) + __blk_run_queue(q); + spin_unlock_irqrestore(q->queue_lock, flags); + + return 0; +} +EXPORT_SYMBOL_GPL(blk_insert_cloned_request); + +/** + * blk_rq_err_bytes - determine number of bytes till the next failure boundary + * @rq: request to examine + * + * Description: + * A request could be merge of IOs which require different failure + * handling. This function determines the number of bytes which + * can be failed from the beginning of the request without + * crossing into area which need to be retried further. + * + * Return: + * The number of bytes to fail. + * + * Context: + * queue_lock must be held. + */ +unsigned int blk_rq_err_bytes(const struct request *rq) +{ + unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; + unsigned int bytes = 0; + struct bio *bio; + + if (!(rq->cmd_flags & REQ_MIXED_MERGE)) + return blk_rq_bytes(rq); + + /* + * Currently the only 'mixing' which can happen is between + * different fastfail types. We can safely fail portions + * which have all the failfast bits that the first one has - + * the ones which are at least as eager to fail as the first + * one. + */ + for (bio = rq->bio; bio; bio = bio->bi_next) { + if ((bio->bi_rw & ff) != ff) + break; + bytes += bio->bi_iter.bi_size; + } + + /* this could lead to infinite loop */ + BUG_ON(blk_rq_bytes(rq) && !bytes); + return bytes; +} +EXPORT_SYMBOL_GPL(blk_rq_err_bytes); + +void blk_account_io_completion(struct request *req, unsigned int bytes) +{ + if (blk_do_io_stat(req)) { + const int rw = rq_data_dir(req); + struct hd_struct *part; + int cpu; + + cpu = part_stat_lock(); + part = req->part; + part_stat_add(cpu, part, sectors[rw], bytes >> 9); + part_stat_unlock(); + } +} + +void blk_account_io_done(struct request *req) +{ + /* + * Account IO completion. flush_rq isn't accounted as a + * normal IO on queueing nor completion. Accounting the + * containing request is enough. + */ + if (blk_do_io_stat(req) && !(req->cmd_flags & REQ_FLUSH_SEQ)) { + unsigned long duration = jiffies - req->start_time; + const int rw = rq_data_dir(req); + struct hd_struct *part; + int cpu; + + cpu = part_stat_lock(); + part = req->part; + + part_stat_inc(cpu, part, ios[rw]); + part_stat_add(cpu, part, ticks[rw], duration); + part_round_stats(cpu, part); + part_dec_in_flight(part, rw); + + hd_struct_put(part); + part_stat_unlock(); + } +} + +#ifdef CONFIG_PM +/* + * Don't process normal requests when queue is suspended + * or in the process of suspending/resuming + */ +static struct request *blk_pm_peek_request(struct request_queue *q, + struct request *rq) +{ + if (q->dev && (q->rpm_status == RPM_SUSPENDED || + (q->rpm_status != RPM_ACTIVE && !(rq->cmd_flags & REQ_PM)))) + return NULL; + else + return rq; +} +#else +static inline struct request *blk_pm_peek_request(struct request_queue *q, + struct request *rq) +{ + return rq; +} +#endif + +void blk_account_io_start(struct request *rq, bool new_io) +{ + struct hd_struct *part; + int rw = rq_data_dir(rq); + int cpu; + + if (!blk_do_io_stat(rq)) + return; + + cpu = part_stat_lock(); + + if (!new_io) { + part = rq->part; + part_stat_inc(cpu, part, merges[rw]); + } else { + part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq)); + if (!hd_struct_try_get(part)) { + /* + * The partition is already being removed, + * the request will be accounted on the disk only + * + * We take a reference on disk->part0 although that + * partition will never be deleted, so we can treat + * it as any other partition. + */ + part = &rq->rq_disk->part0; + hd_struct_get(part); + } + part_round_stats(cpu, part); + part_inc_in_flight(part, rw); + rq->part = part; + } + + part_stat_unlock(); +} + +/** + * blk_peek_request - peek at the top of a request queue + * @q: request queue to peek at + * + * Description: + * Return the request at the top of @q. The returned request + * should be started using blk_start_request() before LLD starts + * processing it. + * + * Return: + * Pointer to the request at the top of @q if available. Null + * otherwise. + * + * Context: + * queue_lock must be held. + */ +struct request *blk_peek_request(struct request_queue *q) +{ + struct request *rq; + int ret; + + while ((rq = __elv_next_request(q)) != NULL) { + + rq = blk_pm_peek_request(q, rq); + if (!rq) + break; + + if (!(rq->cmd_flags & REQ_STARTED)) { + /* + * This is the first time the device driver + * sees this request (possibly after + * requeueing). Notify IO scheduler. + */ + if (rq->cmd_flags & REQ_SORTED) + elv_activate_rq(q, rq); + + /* + * just mark as started even if we don't start + * it, a request that has been delayed should + * not be passed by new incoming requests + */ + rq->cmd_flags |= REQ_STARTED; + trace_block_rq_issue(q, rq); + } + + if (!q->boundary_rq || q->boundary_rq == rq) { + q->end_sector = rq_end_sector(rq); + q->boundary_rq = NULL; + } + + if (rq->cmd_flags & REQ_DONTPREP) + break; + + if (q->dma_drain_size && blk_rq_bytes(rq)) { + /* + * make sure space for the drain appears we + * know we can do this because max_hw_segments + * has been adjusted to be one fewer than the + * device can handle + */ + rq->nr_phys_segments++; + } + + if (!q->prep_rq_fn) + break; + + ret = q->prep_rq_fn(q, rq); + if (ret == BLKPREP_OK) { + break; + } else if (ret == BLKPREP_DEFER) { + /* + * the request may have been (partially) prepped. + * we need to keep this request in the front to + * avoid resource deadlock. REQ_STARTED will + * prevent other fs requests from passing this one. + */ + if (q->dma_drain_size && blk_rq_bytes(rq) && + !(rq->cmd_flags & REQ_DONTPREP)) { + /* + * remove the space for the drain we added + * so that we don't add it again + */ + --rq->nr_phys_segments; + } + + rq = NULL; + break; + } else if (ret == BLKPREP_KILL) { + rq->cmd_flags |= REQ_QUIET; + /* + * Mark this request as started so we don't trigger + * any debug logic in the end I/O path. + */ + blk_start_request(rq); + __blk_end_request_all(rq, -EIO); + } else { + printk(KERN_ERR "%s: bad return=%d\n", __func__, ret); + break; + } + } + + return rq; +} +EXPORT_SYMBOL(blk_peek_request); + +void blk_dequeue_request(struct request *rq) +{ + struct request_queue *q = rq->q; + + BUG_ON(list_empty(&rq->queuelist)); + BUG_ON(ELV_ON_HASH(rq)); + + list_del_init(&rq->queuelist); + + /* + * the time frame between a request being removed from the lists + * and to it is freed is accounted as io that is in progress at + * the driver side. + */ + if (blk_account_rq(rq)) { + q->in_flight[rq_is_sync(rq)]++; + set_io_start_time_ns(rq); + } +} + +/** + * blk_start_request - start request processing on the driver + * @req: request to dequeue + * + * Description: + * Dequeue @req and start timeout timer on it. This hands off the + * request to the driver. + * + * Block internal functions which don't want to start timer should + * call blk_dequeue_request(). + * + * Context: + * queue_lock must be held. + */ +void blk_start_request(struct request *req) +{ + blk_dequeue_request(req); + + /* + * We are now handing the request to the hardware, initialize + * resid_len to full count and add the timeout handler. + */ + req->resid_len = blk_rq_bytes(req); + if (unlikely(blk_bidi_rq(req))) + req->next_rq->resid_len = blk_rq_bytes(req->next_rq); + + BUG_ON(test_bit(REQ_ATOM_COMPLETE, &req->atomic_flags)); + blk_add_timer(req); +} +EXPORT_SYMBOL(blk_start_request); + +/** + * blk_fetch_request - fetch a request from a request queue + * @q: request queue to fetch a request from + * + * Description: + * Return the request at the top of @q. The request is started on + * return and LLD can start processing it immediately. + * + * Return: + * Pointer to the request at the top of @q if available. Null + * otherwise. + * + * Context: + * queue_lock must be held. + */ +struct request *blk_fetch_request(struct request_queue *q) +{ + struct request *rq; + + rq = blk_peek_request(q); + if (rq) + blk_start_request(rq); + return rq; +} +EXPORT_SYMBOL(blk_fetch_request); + +/** + * blk_update_request - Special helper function for request stacking drivers + * @req: the request being processed + * @error: %0 for success, < %0 for error + * @nr_bytes: number of bytes to complete @req + * + * Description: + * Ends I/O on a number of bytes attached to @req, but doesn't complete + * the request structure even if @req doesn't have leftover. + * If @req has leftover, sets it up for the next range of segments. + * + * This special helper function is only for request stacking drivers + * (e.g. request-based dm) so that they can handle partial completion. + * Actual device drivers should use blk_end_request instead. + * + * Passing the result of blk_rq_bytes() as @nr_bytes guarantees + * %false return from this function. + * + * Return: + * %false - this request doesn't have any more data + * %true - this request has more data + **/ +bool blk_update_request(struct request *req, int error, unsigned int nr_bytes) +{ + int total_bytes; + + trace_block_rq_complete(req->q, req, nr_bytes); + + if (!req->bio) + return false; + + /* + * For fs requests, rq is just carrier of independent bio's + * and each partial completion should be handled separately. + * Reset per-request error on each partial completion. + * + * TODO: tj: This is too subtle. It would be better to let + * low level drivers do what they see fit. + */ + if (req->cmd_type == REQ_TYPE_FS) + req->errors = 0; + + if (error && req->cmd_type == REQ_TYPE_FS && + !(req->cmd_flags & REQ_QUIET)) { + char *error_type; + + switch (error) { + case -ENOLINK: + error_type = "recoverable transport"; + break; + case -EREMOTEIO: + error_type = "critical target"; + break; + case -EBADE: + error_type = "critical nexus"; + break; + case -ETIMEDOUT: + error_type = "timeout"; + break; + case -ENOSPC: + error_type = "critical space allocation"; + break; + case -ENODATA: + error_type = "critical medium"; + break; + case -EIO: + default: + error_type = "I/O"; + break; + } + printk_ratelimited(KERN_ERR "%s: %s error, dev %s, sector %llu\n", + __func__, error_type, req->rq_disk ? + req->rq_disk->disk_name : "?", + (unsigned long long)blk_rq_pos(req)); + + } + + blk_account_io_completion(req, nr_bytes); + + total_bytes = 0; + while (req->bio) { + struct bio *bio = req->bio; + unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes); + + if (bio_bytes == bio->bi_iter.bi_size) + req->bio = bio->bi_next; + + req_bio_endio(req, bio, bio_bytes, error); + + total_bytes += bio_bytes; + nr_bytes -= bio_bytes; + + if (!nr_bytes) + break; + } + + /* + * completely done + */ + if (!req->bio) { + /* + * Reset counters so that the request stacking driver + * can find how many bytes remain in the request + * later. + */ + req->__data_len = 0; + return false; + } + + req->__data_len -= total_bytes; + + /* update sector only for requests with clear definition of sector */ + if (req->cmd_type == REQ_TYPE_FS) + req->__sector += total_bytes >> 9; + + /* mixed attributes always follow the first bio */ + if (req->cmd_flags & REQ_MIXED_MERGE) { + req->cmd_flags &= ~REQ_FAILFAST_MASK; + req->cmd_flags |= req->bio->bi_rw & REQ_FAILFAST_MASK; + } + + /* + * If total number of sectors is less than the first segment + * size, something has gone terribly wrong. + */ + if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { + blk_dump_rq_flags(req, "request botched"); + req->__data_len = blk_rq_cur_bytes(req); + } + + /* recalculate the number of segments */ + blk_recalc_rq_segments(req); + + return true; +} +EXPORT_SYMBOL_GPL(blk_update_request); + +static bool blk_update_bidi_request(struct request *rq, int error, + unsigned int nr_bytes, + unsigned int bidi_bytes) +{ + if (blk_update_request(rq, error, nr_bytes)) + return true; + + /* Bidi request must be completed as a whole */ + if (unlikely(blk_bidi_rq(rq)) && + blk_update_request(rq->next_rq, error, bidi_bytes)) + return true; + + if (blk_queue_add_random(rq->q)) + add_disk_randomness(rq->rq_disk); + + return false; +} + +/** + * blk_unprep_request - unprepare a request + * @req: the request + * + * This function makes a request ready for complete resubmission (or + * completion). It happens only after all error handling is complete, + * so represents the appropriate moment to deallocate any resources + * that were allocated to the request in the prep_rq_fn. The queue + * lock is held when calling this. + */ +void blk_unprep_request(struct request *req) +{ + struct request_queue *q = req->q; + + req->cmd_flags &= ~REQ_DONTPREP; + if (q->unprep_rq_fn) + q->unprep_rq_fn(q, req); +} +EXPORT_SYMBOL_GPL(blk_unprep_request); + +/* + * queue lock must be held + */ +void blk_finish_request(struct request *req, int error) +{ + if (req->cmd_flags & REQ_QUEUED) + blk_queue_end_tag(req->q, req); + + BUG_ON(blk_queued_rq(req)); + + if (unlikely(laptop_mode) && req->cmd_type == REQ_TYPE_FS) + laptop_io_completion(&req->q->backing_dev_info); + + blk_delete_timer(req); + + if (req->cmd_flags & REQ_DONTPREP) + blk_unprep_request(req); + + blk_account_io_done(req); + + if (req->end_io) + req->end_io(req, error); + else { + if (blk_bidi_rq(req)) + __blk_put_request(req->next_rq->q, req->next_rq); + + __blk_put_request(req->q, req); + } +} +EXPORT_SYMBOL(blk_finish_request); + +/** + * blk_end_bidi_request - Complete a bidi request + * @rq: the request to complete + * @error: %0 for success, < %0 for error + * @nr_bytes: number of bytes to complete @rq + * @bidi_bytes: number of bytes to complete @rq->next_rq + * + * Description: + * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. + * Drivers that supports bidi can safely call this member for any + * type of request, bidi or uni. In the later case @bidi_bytes is + * just ignored. + * + * Return: + * %false - we are done with this request + * %true - still buffers pending for this request + **/ +static bool blk_end_bidi_request(struct request *rq, int error, + unsigned int nr_bytes, unsigned int bidi_bytes) +{ + struct request_queue *q = rq->q; + unsigned long flags; + + if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) + return true; + + spin_lock_irqsave(q->queue_lock, flags); + blk_finish_request(rq, error); + spin_unlock_irqrestore(q->queue_lock, flags); + + return false; +} + +/** + * __blk_end_bidi_request - Complete a bidi request with queue lock held + * @rq: the request to complete + * @error: %0 for success, < %0 for error + * @nr_bytes: number of bytes to complete @rq + * @bidi_bytes: number of bytes to complete @rq->next_rq + * + * Description: + * Identical to blk_end_bidi_request() except that queue lock is + * assumed to be locked on entry and remains so on return. + * + * Return: + * %false - we are done with this request + * %true - still buffers pending for this request + **/ +bool __blk_end_bidi_request(struct request *rq, int error, + unsigned int nr_bytes, unsigned int bidi_bytes) +{ + if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) + return true; + + blk_finish_request(rq, error); + + return false; +} + +/** + * blk_end_request - Helper function for drivers to complete the request. + * @rq: the request being processed + * @error: %0 for success, < %0 for error + * @nr_bytes: number of bytes to complete + * + * Description: + * Ends I/O on a number of bytes attached to @rq. + * If @rq has leftover, sets it up for the next range of segments. + * + * Return: + * %false - we are done with this request + * %true - still buffers pending for this request + **/ +bool blk_end_request(struct request *rq, int error, unsigned int nr_bytes) +{ + return blk_end_bidi_request(rq, error, nr_bytes, 0); +} +EXPORT_SYMBOL(blk_end_request); + +/** + * blk_end_request_all - Helper function for drives to finish the request. + * @rq: the request to finish + * @error: %0 for success, < %0 for error + * + * Description: + * Completely finish @rq. + */ +void blk_end_request_all(struct request *rq, int error) +{ + bool pending; + unsigned int bidi_bytes = 0; + + if (unlikely(blk_bidi_rq(rq))) + bidi_bytes = blk_rq_bytes(rq->next_rq); + + pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); + BUG_ON(pending); +} +EXPORT_SYMBOL(blk_end_request_all); + +/** + * blk_end_request_cur - Helper function to finish the current request chunk. + * @rq: the request to finish the current chunk for + * @error: %0 for success, < %0 for error + * + * Description: + * Complete the current consecutively mapped chunk from @rq. + * + * Return: + * %false - we are done with this request + * %true - still buffers pending for this request + */ +bool blk_end_request_cur(struct request *rq, int error) +{ + return blk_end_request(rq, error, blk_rq_cur_bytes(rq)); +} +EXPORT_SYMBOL(blk_end_request_cur); + +/** + * blk_end_request_err - Finish a request till the next failure boundary. + * @rq: the request to finish till the next failure boundary for + * @error: must be negative errno + * + * Description: + * Complete @rq till the next failure boundary. + * + * Return: + * %false - we are done with this request + * %true - still buffers pending for this request + */ +bool blk_end_request_err(struct request *rq, int error) +{ + WARN_ON(error >= 0); + return blk_end_request(rq, error, blk_rq_err_bytes(rq)); +} +EXPORT_SYMBOL_GPL(blk_end_request_err); + +/** + * __blk_end_request - Helper function for drivers to complete the request. + * @rq: the request being processed + * @error: %0 for success, < %0 for error + * @nr_bytes: number of bytes to complete + * + * Description: + * Must be called with queue lock held unlike blk_end_request(). + * + * Return: + * %false - we are done with this request + * %true - still buffers pending for this request + **/ +bool __blk_end_request(struct request *rq, int error, unsigned int nr_bytes) +{ + return __blk_end_bidi_request(rq, error, nr_bytes, 0); +} +EXPORT_SYMBOL(__blk_end_request); + +/** + * __blk_end_request_all - Helper function for drives to finish the request. + * @rq: the request to finish + * @error: %0 for success, < %0 for error + * + * Description: + * Completely finish @rq. Must be called with queue lock held. + */ +void __blk_end_request_all(struct request *rq, int error) +{ + bool pending; + unsigned int bidi_bytes = 0; + + if (unlikely(blk_bidi_rq(rq))) + bidi_bytes = blk_rq_bytes(rq->next_rq); + + pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); + BUG_ON(pending); +} +EXPORT_SYMBOL(__blk_end_request_all); + +/** + * __blk_end_request_cur - Helper function to finish the current request chunk. + * @rq: the request to finish the current chunk for + * @error: %0 for success, < %0 for error + * + * Description: + * Complete the current consecutively mapped chunk from @rq. Must + * be called with queue lock held. + * + * Return: + * %false - we are done with this request + * %true - still buffers pending for this request + */ +bool __blk_end_request_cur(struct request *rq, int error) +{ + return __blk_end_request(rq, error, blk_rq_cur_bytes(rq)); +} +EXPORT_SYMBOL(__blk_end_request_cur); + +/** + * __blk_end_request_err - Finish a request till the next failure boundary. + * @rq: the request to finish till the next failure boundary for + * @error: must be negative errno + * + * Description: + * Complete @rq till the next failure boundary. Must be called + * with queue lock held. + * + * Return: + * %false - we are done with this request + * %true - still buffers pending for this request + */ +bool __blk_end_request_err(struct request *rq, int error) +{ + WARN_ON(error >= 0); + return __blk_end_request(rq, error, blk_rq_err_bytes(rq)); +} +EXPORT_SYMBOL_GPL(__blk_end_request_err); + +void blk_rq_bio_prep(struct request_queue *q, struct request *rq, + struct bio *bio) +{ + /* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw */ + rq->cmd_flags |= bio->bi_rw & REQ_WRITE; + + if (bio_has_data(bio)) + rq->nr_phys_segments = bio_phys_segments(q, bio); + + rq->__data_len = bio->bi_iter.bi_size; + rq->bio = rq->biotail = bio; + + if (bio->bi_bdev) + rq->rq_disk = bio->bi_bdev->bd_disk; +} + +#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE +/** + * rq_flush_dcache_pages - Helper function to flush all pages in a request + * @rq: the request to be flushed + * + * Description: + * Flush all pages in @rq. + */ +void rq_flush_dcache_pages(struct request *rq) +{ + struct req_iterator iter; + struct bio_vec bvec; + + rq_for_each_segment(bvec, rq, iter) + flush_dcache_page(bvec.bv_page); +} +EXPORT_SYMBOL_GPL(rq_flush_dcache_pages); +#endif + +/** + * blk_lld_busy - Check if underlying low-level drivers of a device are busy + * @q : the queue of the device being checked + * + * Description: + * Check if underlying low-level drivers of a device are busy. + * If the drivers want to export their busy state, they must set own + * exporting function using blk_queue_lld_busy() first. + * + * Basically, this function is used only by request stacking drivers + * to stop dispatching requests to underlying devices when underlying + * devices are busy. This behavior helps more I/O merging on the queue + * of the request stacking driver and prevents I/O throughput regression + * on burst I/O load. + * + * Return: + * 0 - Not busy (The request stacking driver should dispatch request) + * 1 - Busy (The request stacking driver should stop dispatching request) + */ +int blk_lld_busy(struct request_queue *q) +{ + if (q->lld_busy_fn) + return q->lld_busy_fn(q); + + return 0; +} +EXPORT_SYMBOL_GPL(blk_lld_busy); + +/** + * blk_rq_unprep_clone - Helper function to free all bios in a cloned request + * @rq: the clone request to be cleaned up + * + * Description: + * Free all bios in @rq for a cloned request. + */ +void blk_rq_unprep_clone(struct request *rq) +{ + struct bio *bio; + + while ((bio = rq->bio) != NULL) { + rq->bio = bio->bi_next; + + bio_put(bio); + } +} +EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); + +/* + * Copy attributes of the original request to the clone request. + * The actual data parts (e.g. ->cmd, ->sense) are not copied. + */ +static void __blk_rq_prep_clone(struct request *dst, struct request *src) +{ + dst->cpu = src->cpu; + dst->cmd_flags |= (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE; + dst->cmd_type = src->cmd_type; + dst->__sector = blk_rq_pos(src); + dst->__data_len = blk_rq_bytes(src); + dst->nr_phys_segments = src->nr_phys_segments; + dst->ioprio = src->ioprio; + dst->extra_len = src->extra_len; +} + +/** + * blk_rq_prep_clone - Helper function to setup clone request + * @rq: the request to be setup + * @rq_src: original request to be cloned + * @bs: bio_set that bios for clone are allocated from + * @gfp_mask: memory allocation mask for bio + * @bio_ctr: setup function to be called for each clone bio. + * Returns %0 for success, non %0 for failure. + * @data: private data to be passed to @bio_ctr + * + * Description: + * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. + * The actual data parts of @rq_src (e.g. ->cmd, ->sense) + * are not copied, and copying such parts is the caller's responsibility. + * Also, pages which the original bios are pointing to are not copied + * and the cloned bios just point same pages. + * So cloned bios must be completed before original bios, which means + * the caller must complete @rq before @rq_src. + */ +int blk_rq_prep_clone(struct request *rq, struct request *rq_src, + struct bio_set *bs, gfp_t gfp_mask, + int (*bio_ctr)(struct bio *, struct bio *, void *), + void *data) +{ + struct bio *bio, *bio_src; + + if (!bs) + bs = fs_bio_set; + + __rq_for_each_bio(bio_src, rq_src) { + bio = bio_clone_fast(bio_src, gfp_mask, bs); + if (!bio) + goto free_and_out; + + if (bio_ctr && bio_ctr(bio, bio_src, data)) + goto free_and_out; + + if (rq->bio) { + rq->biotail->bi_next = bio; + rq->biotail = bio; + } else + rq->bio = rq->biotail = bio; + } + + __blk_rq_prep_clone(rq, rq_src); + + return 0; + +free_and_out: + if (bio) + bio_put(bio); + blk_rq_unprep_clone(rq); + + return -ENOMEM; +} +EXPORT_SYMBOL_GPL(blk_rq_prep_clone); + +int kblockd_schedule_work(struct work_struct *work) +{ + return queue_work(kblockd_workqueue, work); +} +EXPORT_SYMBOL(kblockd_schedule_work); + +int kblockd_schedule_delayed_work(struct delayed_work *dwork, + unsigned long delay) +{ + return queue_delayed_work(kblockd_workqueue, dwork, delay); +} +EXPORT_SYMBOL(kblockd_schedule_delayed_work); + +int kblockd_schedule_delayed_work_on(int cpu, struct delayed_work *dwork, + unsigned long delay) +{ + return queue_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); +} +EXPORT_SYMBOL(kblockd_schedule_delayed_work_on); + +/** + * blk_start_plug - initialize blk_plug and track it inside the task_struct + * @plug: The &struct blk_plug that needs to be initialized + * + * Description: + * Tracking blk_plug inside the task_struct will help with auto-flushing the + * pending I/O should the task end up blocking between blk_start_plug() and + * blk_finish_plug(). This is important from a performance perspective, but + * also ensures that we don't deadlock. For instance, if the task is blocking + * for a memory allocation, memory reclaim could end up wanting to free a + * page belonging to that request that is currently residing in our private + * plug. By flushing the pending I/O when the process goes to sleep, we avoid + * this kind of deadlock. + */ +void blk_start_plug(struct blk_plug *plug) +{ + struct task_struct *tsk = current; + + INIT_LIST_HEAD(&plug->list); + INIT_LIST_HEAD(&plug->mq_list); + INIT_LIST_HEAD(&plug->cb_list); + + /* + * If this is a nested plug, don't actually assign it. It will be + * flushed on its own. + */ + if (!tsk->plug) { + /* + * Store ordering should not be needed here, since a potential + * preempt will imply a full memory barrier + */ + tsk->plug = plug; + } +} +EXPORT_SYMBOL(blk_start_plug); + +static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) +{ + struct request *rqa = container_of(a, struct request, queuelist); + struct request *rqb = container_of(b, struct request, queuelist); + + return !(rqa->q < rqb->q || + (rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb))); +} + +/* + * If 'from_schedule' is true, then postpone the dispatch of requests + * until a safe kblockd context. We due this to avoid accidental big + * additional stack usage in driver dispatch, in places where the originally + * plugger did not intend it. + */ +static void queue_unplugged(struct request_queue *q, unsigned int depth, + bool from_schedule) + __releases(q->queue_lock) +{ + trace_block_unplug(q, depth, !from_schedule); + + if (from_schedule) + blk_run_queue_async(q); + else + __blk_run_queue(q); + spin_unlock(q->queue_lock); +} + +static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) +{ + LIST_HEAD(callbacks); + + while (!list_empty(&plug->cb_list)) { + list_splice_init(&plug->cb_list, &callbacks); + + while (!list_empty(&callbacks)) { + struct blk_plug_cb *cb = list_first_entry(&callbacks, + struct blk_plug_cb, + list); + list_del(&cb->list); + cb->callback(cb, from_schedule); + } + } +} + +struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, + int size) +{ + struct blk_plug *plug = current->plug; + struct blk_plug_cb *cb; + + if (!plug) + return NULL; + + list_for_each_entry(cb, &plug->cb_list, list) + if (cb->callback == unplug && cb->data == data) + return cb; + + /* Not currently on the callback list */ + BUG_ON(size < sizeof(*cb)); + cb = kzalloc(size, GFP_ATOMIC); + if (cb) { + cb->data = data; + cb->callback = unplug; + list_add(&cb->list, &plug->cb_list); + } + return cb; +} +EXPORT_SYMBOL(blk_check_plugged); + +void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) +{ + struct request_queue *q; + unsigned long flags; + struct request *rq; + LIST_HEAD(list); + unsigned int depth; + + flush_plug_callbacks(plug, from_schedule); + + if (!list_empty(&plug->mq_list)) + blk_mq_flush_plug_list(plug, from_schedule); + + if (list_empty(&plug->list)) + return; + + list_splice_init(&plug->list, &list); + + list_sort(NULL, &list, plug_rq_cmp); + + q = NULL; + depth = 0; + + /* + * Save and disable interrupts here, to avoid doing it for every + * queue lock we have to take. + */ + local_irq_save(flags); + while (!list_empty(&list)) { + rq = list_entry_rq(list.next); + list_del_init(&rq->queuelist); + BUG_ON(!rq->q); + if (rq->q != q) { + /* + * This drops the queue lock + */ + if (q) + queue_unplugged(q, depth, from_schedule); + q = rq->q; + depth = 0; + spin_lock(q->queue_lock); + } + + /* + * Short-circuit if @q is dead + */ + if (unlikely(blk_queue_dying(q))) { + __blk_end_request_all(rq, -ENODEV); + continue; + } + + /* + * rq is already accounted, so use raw insert + */ + if (rq->cmd_flags & (REQ_FLUSH | REQ_FUA)) + __elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH); + else + __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE); + + depth++; + } + + /* + * This drops the queue lock + */ + if (q) + queue_unplugged(q, depth, from_schedule); + + local_irq_restore(flags); +} + +void blk_finish_plug(struct blk_plug *plug) +{ + blk_flush_plug_list(plug, false); + + if (plug == current->plug) + current->plug = NULL; +} +EXPORT_SYMBOL(blk_finish_plug); + +#ifdef CONFIG_PM +/** + * blk_pm_runtime_init - Block layer runtime PM initialization routine + * @q: the queue of the device + * @dev: the device the queue belongs to + * + * Description: + * Initialize runtime-PM-related fields for @q and start auto suspend for + * @dev. Drivers that want to take advantage of request-based runtime PM + * should call this function after @dev has been initialized, and its + * request queue @q has been allocated, and runtime PM for it can not happen + * yet(either due to disabled/forbidden or its usage_count > 0). In most + * cases, driver should call this function before any I/O has taken place. + * + * This function takes care of setting up using auto suspend for the device, + * the autosuspend delay is set to -1 to make runtime suspend impossible + * until an updated value is either set by user or by driver. Drivers do + * not need to touch other autosuspend settings. + * + * The block layer runtime PM is request based, so only works for drivers + * that use request as their IO unit instead of those directly use bio's. + */ +void blk_pm_runtime_init(struct request_queue *q, struct device *dev) +{ + q->dev = dev; + q->rpm_status = RPM_ACTIVE; + pm_runtime_set_autosuspend_delay(q->dev, -1); + pm_runtime_use_autosuspend(q->dev); +} +EXPORT_SYMBOL(blk_pm_runtime_init); + +/** + * blk_pre_runtime_suspend - Pre runtime suspend check + * @q: the queue of the device + * + * Description: + * This function will check if runtime suspend is allowed for the device + * by examining if there are any requests pending in the queue. If there + * are requests pending, the device can not be runtime suspended; otherwise, + * the queue's status will be updated to SUSPENDING and the driver can + * proceed to suspend the device. + * + * For the not allowed case, we mark last busy for the device so that + * runtime PM core will try to autosuspend it some time later. + * + * This function should be called near the start of the device's + * runtime_suspend callback. + * + * Return: + * 0 - OK to runtime suspend the device + * -EBUSY - Device should not be runtime suspended + */ +int blk_pre_runtime_suspend(struct request_queue *q) +{ + int ret = 0; + + spin_lock_irq(q->queue_lock); + if (q->nr_pending) { + ret = -EBUSY; + pm_runtime_mark_last_busy(q->dev); + } else { + q->rpm_status = RPM_SUSPENDING; + } + spin_unlock_irq(q->queue_lock); + return ret; +} +EXPORT_SYMBOL(blk_pre_runtime_suspend); + +/** + * blk_post_runtime_suspend - Post runtime suspend processing + * @q: the queue of the device + * @err: return value of the device's runtime_suspend function + * + * Description: + * Update the queue's runtime status according to the return value of the + * device's runtime suspend function and mark last busy for the device so + * that PM core will try to auto suspend the device at a later time. + * + * This function should be called near the end of the device's + * runtime_suspend callback. + */ +void blk_post_runtime_suspend(struct request_queue *q, int err) +{ + spin_lock_irq(q->queue_lock); + if (!err) { + q->rpm_status = RPM_SUSPENDED; + } else { + q->rpm_status = RPM_ACTIVE; + pm_runtime_mark_last_busy(q->dev); + } + spin_unlock_irq(q->queue_lock); +} +EXPORT_SYMBOL(blk_post_runtime_suspend); + +/** + * blk_pre_runtime_resume - Pre runtime resume processing + * @q: the queue of the device + * + * Description: + * Update the queue's runtime status to RESUMING in preparation for the + * runtime resume of the device. + * + * This function should be called near the start of the device's + * runtime_resume callback. + */ +void blk_pre_runtime_resume(struct request_queue *q) +{ + spin_lock_irq(q->queue_lock); + q->rpm_status = RPM_RESUMING; + spin_unlock_irq(q->queue_lock); +} +EXPORT_SYMBOL(blk_pre_runtime_resume); + +/** + * blk_post_runtime_resume - Post runtime resume processing + * @q: the queue of the device + * @err: return value of the device's runtime_resume function + * + * Description: + * Update the queue's runtime status according to the return value of the + * device's runtime_resume function. If it is successfully resumed, process + * the requests that are queued into the device's queue when it is resuming + * and then mark last busy and initiate autosuspend for it. + * + * This function should be called near the end of the device's + * runtime_resume callback. + */ +void blk_post_runtime_resume(struct request_queue *q, int err) +{ + spin_lock_irq(q->queue_lock); + if (!err) { + q->rpm_status = RPM_ACTIVE; + __blk_run_queue(q); + pm_runtime_mark_last_busy(q->dev); + pm_request_autosuspend(q->dev); + } else { + q->rpm_status = RPM_SUSPENDED; + } + spin_unlock_irq(q->queue_lock); +} +EXPORT_SYMBOL(blk_post_runtime_resume); +#endif + +int __init blk_dev_init(void) +{ + BUILD_BUG_ON(__REQ_NR_BITS > 8 * + sizeof(((struct request *)0)->cmd_flags)); + + /* used for unplugging and affects IO latency/throughput - HIGHPRI */ + kblockd_workqueue = alloc_workqueue("kblockd", + WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); + if (!kblockd_workqueue) + panic("Failed to create kblockd\n"); + + request_cachep = kmem_cache_create("blkdev_requests", + sizeof(struct request), 0, SLAB_PANIC, NULL); + + blk_requestq_cachep = kmem_cache_create("blkdev_queue", + sizeof(struct request_queue), 0, SLAB_PANIC, NULL); + + return 0; +} |